Why Is One Side Of A Public Double Door Always Locked?

Have you ever noticed that one side of a public double door is inevitably locked? Have you ever stopped to think about what the purpose of this might be? This is where you will find out many of the possible explanations for this troubling phenomenon.


Sometimes people are too lazy to open the second door when the first door will suffice. This is not a great explanation, but it is often the case. This is especially true when you find that the double doors in question are both open some days and one is locked on others.


Sometimes one side of a public double door always being locked is attributed to safety issues. It can be a spill behind the doors or a windy day where the force of the wind could blow the doors open quickly to strike someone in the face. This has happened, so this is a reason why some double doors have one side locked at all times.

Temperature Control

With two doors opening and closing all the time, it can be harder to maintain a comfortable temperature inside of a building. It costs more to try to maintain the temperature this way, too. Temperature control is yet another possible reason for the locking of one of the doors, although this may not be the main reason most of the time.

Traffic Flow

Occasionally, you will find those who claim that having one door locked helps to control the flow of traffic in and out of a building. This seems like a silly reason as it seems like it can’t make that much of a difference, but it is worth mentioning because it is cited as a reason. Not a good one but a reason nonetheless.

Closing Time

A slightly more understandable reason is that at closing time both doors must be locked. When these types of double doors are locked they can still swing freely on their hinges unless the truly stationary door has been secured in place using its special additional switches. To make sure they don’t forget to secure the switches of this second door so that it can’t swing on hinges, many establishments leave it locked and secured all the time.

Emergency Exit

Another explanation that sounds somewhat feasible is that the second door is meant only as an emergency door. In the case of an emergency, this second door may be opened so that individuals may escape the building more quickly. Why the doors wouldn’t both be left open to ensure that they will be open should an emergency occur is anybody’s guess. This may not describe an ideal situation, but it does provide a legitimate reason to have that second door, even if it is not open the overwhelming majority of the time.


As difficult as it may be to believe, the second door can be locked because it is broken. After all, it is easier to lock the door than fix it. This explanation may make this entry part of the first category, though.

These are reasons that people give for why one side of a public double door is always locked. There seems to be little consensus, so the provided reason may just depend upon where the doors are or the person you ask. Still, these explanations let you know what you are likely to hear as a response if you take the time to ask this question of the people who are deciding what doors stay open and what doors stay locked.